Method and apparatus for treating wide webs in the presence of a high vacuum

ABSTRACT

A METHOD OF CARRYING A WEB FROM ATMOSPHERIC CONDITIONS INTO A HIGH-VACUUM CHAMBER FOR TREATING ONE SURFACE OF THE WEB AND FOR RETURNING THE TREATED WEB TO AN AREA AT ATMOSPHERIC CONDITIONS, AND A COMPACT APPARATUS FOR SEALING A HIGH-VACUUM CHAMBER WHILE PERMITTING THE FREE AND RAPID MOVEMENT OF A WEB FROM THE ATMOSPHERE INTO THE HIGH VACUUM CHAMBER FOR TREATMENT AS BY A CORPUSCULAR BEAM AND THE RETURN OF THE WEB TO AN AREA AT ATMOSPHERIC PRESSURE.

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METHOD AND APPARATUS FOR TREATING WlDE WEBS IN THE PRESENCE OF A HIGH VACUUM jam 5,

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METHOD AND APPARATUS FOR TREATING WIDE WEBS IN THE PRESENCE OF A HIGH VACUUM Filed June 15, 1968 4 Sheets-Sheet 2.

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Jan. 5, 1973 D. A. JONES 3,553,709

METHOD AND APPARATUSFOR TREATING WIDE WEBS IN THE PRESENCE OF A HIGH VACUUM Filed June 15, 1968 4 Sheets-Sheet 5 INVENTOR.

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METHOD AND APPARATUS FOR TREATING WIDE WEBS IN THE PRESENCE OF A HIGH VACUUM Filed June 13. 1968 4 Sheets-Sheet 4 United States Patent 3,553,709 METHOD AND APPARATUS FOR TREATING WIDE WEBS IN THE PRESENCE OF A HIGH VACUUM Derrick A. Jones, Woodbury Township, Ramsey County,

Minn., assignor to Minnesota Mining and Manufacturing Company, St. Paul, Minn., a corporation of Delaware Continuation-impart of application Ser. No. 613,215, Feb. 1, 1967. This application June 13, 1968, Ser. No. 736,818

Int. Cl. G01d /14 US. Cl. 346-4 16 Claims ABSTRACT OF THE DISCLOSURE A method of carrying a web from atmospheric conditions into a high-vacuum chamber for treating one surface of the web and for returning the treated web to an area at atmospheric conditions, and a compact apparatus for sealing a high-vacuum chamber while permitting the free and rapid movement of a web from the atmosphere into the high vacuum chamber for treatment as by a corpuscular beam and the return of the web to an area at atmospheric pressure.

This application is a continuation-in-part of application Ser. No. 613,215, filed Feb. 1, 1967, now abandoned.

The present invention relates to an improved method and apparatus for the treating of a web material under high-vacuum conditions, as by a corpuscular beam, and in one aspect to a system which affords the rapid movement of web material of any size from an area typically at atmospheric pressure into and out of a high-vacuum chamber without disrupting the vacuum and without the need for storing the supply and take-up rolls in large vacuum chambers.

The invention of this application is an improvement over the invention of my earlier copending application Ser. No. 515,049, filed Dec. 20, 1965, which application is now abandoned. The invention of the earlier application provided a transport for a medium, be it a tape, polymeric web, film, treated paper, foil, or the like, from a storage area at atmospheric pressures to a position in register with an aperture in a treatment chamber and then out of said high-vacuum atmosphere. The medium was in contact with the cylindrical surface of the drum at all times during movement to, from, and while in register with an aperture communicating with a high vacuum treatment chamber. In utilizing the prior invention for imaging or readout by a corpuscular beam the cylindrical surface resulted in a curved focal plane. This was tolerable for 16 millimeter formats but the radius of the small drum resulted in much too great a curve for the imaging or readout of an image on a millimeter format. If one increased the radius of the drum to compensate for the increase in size of the image area the weight of the drum would increase which slows down the speed at which the successive frames on the medium can be advanced and registered with the aperture in the treatment chamber. Further, the larger drums would be harder to seal.

The method and apparatus of the present invention provides means by which a web can be transported freely from an atmospheric condition to a high-vacuum chamber and be disposed in substantially a planar position therein or in register with an aperture communicating therewith when treated and may be transported out of the chamber with a very small transport and sealing structure.

The apparatus of the present invention overcomes the problems encountered with earlier known apparatus and has the advantage of being suited for use with wider web materials. The apparatus of the present invention has an advantage in that the web transport is light, permitting rapid advance and register successive frame sections at a treatment aperature. The transport can prevent movement of the web over stationary guides. The apparatus of the present invention reduces the area to be sealed. The trans port avoids any flutter from occurring in the film which is present when a web is drawn through an aperture. The preferred embodiment of the invention could permit dual recording, recording and immediately thereafter coding, or recording and subsequent readout.

Referring now to the drawings, there is illustrated a preferred form of apparatus of the present invention and several embodiments thereof wherein:

FIG. 1 is a fragmentary and partially schematic elevational view of an apparatus involving the principles of the present invention;

FIG. 2 is a fragmentary left end view partly in section of the apparatus of FIGS. 1 and 3;

FIG. 3 is a detailed elevational view showing a portion of the apparatus of FIG. 1 with parts removed for convenience in showing interior members;

FIG. 4 is an enlarged detail view taken along line 44 of FIG. 3;

FIG. 5 is a schematic fragmentary elevational view showing a modification of the apparatus of FIG. 1;

FIG. 6 is a schematic vertical sectional view of a second embodiment of an apparatus involving the principles of the present invention; and

FIG. 7 is a schematic vertical sectional view of a third embodiment of an apparatus constructed in accordance with the present invention and showing a modified web drive.

Referring now to the drawing, there is illustrated an apparatus generally designated by the reference numeral 9 which apparatus is particularly adapted to treat a web 10 in the presence of a high vacuum, for example, a corpuscular beam sensitive film, for the purpose of producing successive photographic images on the web. The sensitive film may be formed of any suitable imaging material supported on a backing. Examples of the imaging materials include silver halide emulsion, diazo materials, thermographic materials and the like. The web might also be a tape with an adhesive coating to be treated by the beam or a backing to be vapor coated.

The apparatus 9 comprises a housing 11, partially shown in FIG. 1 which has spaced vertical walls 12 and 13, a top wall 14 and a vertically positioned wall 15 joining walls 12 and 13 and a horizontal supporting wall 16. To the left of the vertical wall 13 additional equipment and electronics (not shown) can be disposed behind a door, which might operate and control the web for treatment and may provide equipment for development of an imaged web.

The wall 15 is adapted to support a pair of rotatable spindles 17 and 18. Spindle 17 is adapted to rotatably support a supply reel 19 upon which is wound the web 10. Reel 19, if the web is light-sensitive as well as beamsensitive, is carried in a cartridge 21 adapted to be supported on the wall 15 with the reel mounted on spindle 17. The spindle 17 is suitably braked in a controlled manner, as by an electrostatic brake, controlled by a pressureresponsive sensing switch to be hereinafter described.

The spindle 18 is driven by a motor 23 and is adapted to support a take-up reel 24 which is mounted within a cartridge 26'. The motor 23 is controlled through a pressure-responsive sensing switch as hereinafter described. The cartridge 26 encloses the reel 24 and is supported from wall 15.

The web 10 is adapted to be fed from the reel 19 through a slot into a transport and sealing apparatus 30 and is rewound on the take-up reel 24. In the illustrated device for recording images or other information onto a web, the Web is treated in the transport and sealing apparatus 30 by a corpuscular beam generated in a treatment chamber 31. The beam for example, may be generated by an electron gun assembly comprising means for generating and controlling an electron beam such as a cathode 32, an anode 33 and focussing lenses or elec trodes 34 which focuses a beam 35 and directs it through a deflection means (not shown) such as conventional magnetic deflection coils or electrostatic plates in a casing 36 which deflect the beam to position the information. At the upper end of casing 36 as shown in FIG. 1, the beam 35 passes through the end wall of the chamber to impinge directly upon the web 10.

The gun assembly is connected to one side of a plate 37 joining the gun assembly to the lower edge of a first block 38 defining part of a passageway for the web, the end of the gun or treatment chamber and which is bored to form evacuatable cells for aiding in sealing the treatment chamber. The block 38 is generally V-shaped in elevation and has a pair of parallel planar sides 41 and 42. The side 41 is positioned in contact with and is secured to a plate 43. The block 38 is formed with a concave face 44 which is arcuate in the lengthwise direction and straight in the transverse direction. The transverse dimension of the block 38 is only slightly greater, between 2 to mils, than the width of the web to be treated. Plate 37 and block 38 are provided with aligned apertures to form a single rectangular aperture defining a treatment aperture 46 communicating directly with the evacuatable treatment chamber. The aperture 46 is aligned with the gun casing 36 and is positioned adjacent the center of the concave face 44.

The concave face 44 of the block 38 has two areas thereof which are arcuate and of equal radius, and with an intermediate portion formed by the intersection of two generally planar surfaces each of which is generally tangential to a different one of the two arcuate areas of said concave face. Disposed in communication with the arcuate areas of the concave face 44 are spaced transversely extending slots 51, 52, 53 and 54 which are formed in the block 38 and which communicate with face 44 and respectively with transverse borings 56, 57, 58 and 59 formed in the block 38. The slots 51 and 52 are formed on the outer edges of the concave face and communicate with each other by a groove 63, which is formed in the plate 43 directly connecting the slots 51 and 52 and a second groove 64 formed in the plate 43 which connects the borings 56 and 57. Slots 53 and 54 are formed inwardly of the slots 51 and 52 and communicate with each other by a connecting groove 66 and by a groove 67 which are formed in the plate 43. Grooves corresponding to the grooves 63, 64, 66 and 67 are also formed in a flat smooth plate 68 (see FIG. 1) which is hingedly mounted to the plate 43 and is formed to correspond in shape to the dimensions of the plate 43. Plate 68 forms a side plate for the transport and sealing apparatus 30 and a cover permitting easy access to the apparatus 30 to permit threading of the web.

Secured to the plate 43 and disposed in closely spaced coaxial relationship with the arcuate concave surface of the block 38 is a generally cylindrical block 71 which may, as shown, have one segment thereof cut away. Grooves 72, 73, 74 and 76 are formed on the block 71 in opposed relation to the slots 51, 52, 53 and 54 respectively. Three rollers 77, 78 and 79 are mounted in the block 71, or in a cantilever fashion from plate 43, in circumferentially spaced relation on suitable bearings affording free rotation of the rollers about their axes.

These rollers have their outer peripheral surfaces disposed substantially flush or slightly beyond the generally cylindrical surface of the block 71 but prefereably not more than 0.001 inch. The rollers 77, 78 and 79 support a movable transport member 81 which is positioned around the periphery of the block 71 and which is adapted to be movable through the slot formed between the outer cylindrical surface of the block 71 and the mating arcuate areas of the concave face 44 of the block 38. In the embodiment illustrated in FIGS. 1 through 3 the transport member or band 81 takes the form of a rigid cylindrical ring having an outer diameter of about 6 inches (15 cm.) and thin side walls of a uniform rectangular cross section. The inner cylindrical surface of this ring engages the three rollers and the outer smooth cylindrical web supporting surface is spaced from the concave face 44 of the block 38 sufficiently to allow movement of the Web 10 and the transport 81 through the passage with clearance of about 00015 inch (0.03 mm.).

A guade roller 82 is disposed in spaced relation to the intersection of the generally planar surfaces of the concave face. This roller 82 is spaced from the concave surface in the block 38 and affords a guide for directing or lifting the web 10 off the surface of the transport ring 81, which may be formed of steel or glass, to position the film as desired for treatment within the highly evecuated area of the passageway. In the illustrated apparatus the web 10 is positioned in a planar position adjacent the rectangular treatment aperture 46 in the block 38. The guide roller 82 then guides the film back to the surface of the ring 81 to be transported thereby between the arcuate surface of block 38 and the outer cylindrical surface of the ring past the slots 54 and 52.

The plate 68 hinged to the plate 43 together with transversely extending plates 86, 87, 88, 89' and 91 form a pair of vacuum chambers 92 and 93 which chambers have one edge wall therof positioned generally tangential to the surface of the transport ring 81 and have the other edges thereof disposed adjacent the outer edges of the apparatus 30 and spaced from the block 38 forming inlet and outlet slots for the insertion of the web to be treated and removal of the treated web. The vacuum or loop chambers 92 and 93 are connected through an opening 94 to a single pump 95 or source of subatmospheric pressure to form the loops in the chambers and hold the web against the ring 81. The loops are maintained by conventional pressure-responsive sensing devices 96 and 97 disposed adjacent openings in plate 43 of the loop chambers 92 and 93, respectively. The sensing device 96 in the first loop chamber 92 releases the brake on the supply reel spindle 17 allowing the differential pressure in the chamber to draw the web 10 off of the reel 19, and the sensing device 97 disposed in the chamber 93 affords operation of the motor 23 causing the take-up reel 24 to wind the web thereon and reduce the size of the loop in chamber 93.

The web 10 is transported by means of the ring 81 through the circuitous passageway formed between the block 38 and the cylindrical block 71 and past the slots 51, 72, and 53, 74 disposed along said passageway leading to the high pressure chamber centrally located relative to the passage. Suitable drive means are provided to move the web 10 and the drive means may drive the web, the transport ring, or both. In the illustrated embodiment of FIGS. 1 to 3 a capstan 101 having a high friction outer coating is disposed adjacent one end of the plate 88 to engage the web 10 as it is drawn from the surface of the ring 81 into chamber 93. The capstan 101 is driven from a motor 102 continuously or intermittently. In a preferred embodiment the capstan has an outer circumference of 2 inches, such that one revolution of the capstan will move the web 2 inches, thus advancing the web relative to the aperture 46 the length of one frame when using a 35 millimeter format. A pressure roller assembly 103 comprising axially spaced narrow rollers 104, which are positioned to engage the edges of the web as shown in FIG. 4, is supported on plate 43 with the rollers 104 biased to press the web 10 into driving engagement with the capstan. A crank arm 105, which is pivotally mounted on a bracket 106 supports the rollers 104. A compression spring 107 mounted between one leg of the crank arm 105 and the bracket 106 urges the pressure rollers toward and into engagement with the web.

An idler roller 108 is positioned between the capstan 101 and the transport ring 81. This roller 108 is mounted on a bifurcated shaft 109 which is slidably mounted in a sleeve 111. The sleeve 111 is supported on the plate 43 between the plates 87 and 88. A compression spring 112, supported within the sleeve 111 bears against a shouldered portion on the shaft 109 to bias the idler roller 108 into engagement with the capstan and with the ring 81 to drive the ring upon rotation of the capstan. This drive means affords a system for driving both the web and the ring to transport the web in increments or continuously through the passageway past the treatment aperture. The small mass of the ring 81 and drive elements permit rapid starting, advance and stopping of the web. The machine is capable when using a suitable motor for the capstan of printing 25 frames a second or imaging on a 35 millimeter format 50 inches of film a second.

Also illustrated in FIG. 3 is a small block 114 which is disposed around the roller 82 and positioned between the planar portions of the concave face 44 and the ring 81. This block 114 serves to support the web at the area of the aperture 46 to decrease any possibility of web flutter at this area where the web is subjected to the high vacuum existing in the treatment chamber 31.

For recording by a corpuscular beam or for other treatment of a web by a beam the chamber 31 is evacuated to a pressure of typically about 1 micron of mercury or between 0.1 to 2 microns of mercury by a suitable vacuum pump 116. To maintain this pressure, since the treatment aperture communicates directly with the open passageway during operation to treat a web, a seal must be formed. In the illustrated device a seal is formed by the circuitous impedance paths formed by the curved passageway through which the web is moved. Also, the presence of the slots 51, 53, '4 and 52 increases the impedance since the air flow in the passageways strike the wall portions of block 38 forming these slots and this greatly interrupts any movement of the air toward the high vacuum area. Additionally, slots 51 and 52 are connected by conduits 117 and 118 to a vacuum pump 119 and these slots and the borings 56 and 57 are evacuated to a pressure of about 27 inches (68 cm.) of mercury.

The slots 53 and 54 are evacuated by a vacuum pump 121 connected through conduits 122 and 123 to the borings 58 and 59. These slots are evacuated to about 100 microns of mercury. The circuitous path, the slots and the reduced pressures through the extent of the passageway provide a seal for the treatment chamber and yet permit the web to pass therethrough for treatment without interference and without one surface thereof contacting any stationary guide which could scratch or otherwise deleteriously affect it. The grooves 63, 64 and 65, 67 in plate 43 and in plate 68 are evacuated as are the corresponding slots and these grooves in the plates act to seal the plate 68 to the blocks 38 and 71 and to plates 86 through 91.

Referring now to FIG. 5 it will be seen that the removal from and return of the web to be treated to the supporting surface of the transport member 81 permits a web to undergo two treatments in a small amount of space. As shown in FIG. 5 the block 38 may be formed with an additional aperture 126, spaced and as illustrated positioned approximately 90 relative to the aperture 46, which may communicate with a second treatment chamber 127. If an electron gun is placed in the chamber 127 communicating with aperture 126 additional markings or codes may be imparted to the web. Further, ap-

paratus for projecting or otherwise reading the web may be associated with aperture 126.

The cylindrical block 71 has a greater extent in the device shown in FIG. 5 and would have this configuration if the ring 81 is flexible instead of rigid as provided in the device of FIGS. 1 to 3.

In FIG. 6 the transport and sealing apparatus 130 comprises a first block 131 adapted to be disposed between spaced parallel plates 132 (only one of which is shown). Block 131 illustrated as an integral piece although adapted to be made of several pieces, has one arcuate concave face 133 of constant radius. Transversely extending spaced slots 135, 136, 137 and 138 are formed in the face 133, and slots 135 and 138 are evacuated to a first predetermined pressure, and slots 136 and 137 are connected and evacuated to a second pressure. A treatment aperture 141 is formed in the block centrally of the face 133 and is adapted to communicate directly with an evacuated treatment chamber, usually at a high vacuum. A second, segment-shaped, block 142 having an arcuate convex surface 143, which is of constant radius, about 10 inches (25.4 cm.), is coaxial to the face 133, and is disposed with the convex surface 143 in closely spaced concentric relation to the face 133. For example, the concave face may have a radius of 10.010 inches and the convex surface may have a radius of 10.000 inches. The first and seconds blocks together with the transversely spaced side plates 132 of the apparatus define a narrow circuitous high impedance passage through which a web 145 is moved to be treated when in register with the aperture 141. The block 142 has guide rollers 146 and 147 disposed and rotatably mounted at its ends. Disposed around the second block 142 and around the guide rollers is a transport member 148 in the form of a flexible band or belt 148 which serve to transport the web 145 through the passageway defined between the blocks and the side plates. In this embodiment, loop chambers 149 and 151 draw the web 145 tightly against the belt 148 and movement of the belt advances the web. The belt is driven from a drive capstan or cylinder 152 positioned between the rollers 146 and 147 and beneath the block 142 to engage the belt. The capstan is driven from a motor (not shown) which is controlled by suitable circuitry associated with the treatment apparatus or by a predetermined program. The belt is held in frictional driving contact with the capstan 152 by a pressure roller 153 which is biased as a spring 154 toward the belt and capstan. Movement of the belt by rotation of the capstan thus advances the web 145 from loop chamber 149 into the passageway and past the treatment aperture 141, where it is treated in the presence of a high vacuum. The slots 135, 138 and 136, 137 at various pressures seal the treatment aperture against the ingress of gas surrounding the apparatus 130.

The movable belt 145 carries the web through the narrow passageway without causing any flutter of the web. The radius of the convex surface 143 of block 142 is large enough such that a rectangular frame or section of the web 145 is sufiiciently planar to receive an image on a format corresponding to 35 millimeter (one and three-eighths inch) by means of a corpuscular beam without distortion of the same at the edges.

In the embodiment of the invention illustrated in FIG. 7, wherein the cover plates for the loop chambers and transport are removed, a web 155 is drawn from a supply into one loop chamber 156 of two generally parallelly disposed chambers 156 and 157. From the chamber 156 the web is guided by a roller 158, which to avoid contact with the web and possible scratching is a porous air bearing formed for example of porous polyethylene, into contact with a flexible transport band or belt 159 to be carried through an open arcuate passageway between a first block 161 having a concave face 162 and a second block 163 having a cooperating convex face 164. The concave face 162 has a first portion of constant radius formed with transverse slots 166 and 167, a generally planar portion 7 formed with a rectangular treatment aperture 168 communicating directly with a chamber 169 housing means for generating a corpuscular beam, and a second portion of constant radius formed with slots 171 and 172.

The block 163 has its face 164 formed with convex portions having a constant radius concentric to the arcuate portions of the face 162 and a general planar surface (having only a slight crown to hold the web in fixed position) spaced opposite the planar portion of face 162. Slots 173, 174, 175 and 176 are formed in block 163 in opposed relation to slots 166, 167, 171, and 172. Slots 173, 166, 172, and 176 are in communication and subjected to subatmospheric pressure through a passageway 177 and bore 178 formed in a plate back of the blocks as illustrated in FIG. 7, and slots 167, 174, 171, and 175 are partially evacuated through a passageway 181 and bore 182. The passageways 177 and 181 are subjected to different pressures about 27 inches (68 cm.) of mercury and to about 200-600 microns of :mercury, respectively. Passageways similar to the passageways 177 and 181 are formed in the surface of the cover plate, which plate has been removed as illustrated in FIG. 7, to connect the slots and equalize pressure in each arcuate portion of the web passageway.

The principal difference between the emobdiment of FIG. 7 and that illustrated in FIGS. l-3 and 6 is the film and transport drive system which will now be explained. The belt 159 passes around the block 163 and around a drive capstan 183 spaced from the block such that its peripheral edges are tangential with the convex curved surface portions of the block 163. The web 155, which is placed in contact with the belt 159 at the start of the arcuate differentially evacuated passageway, is carried by the belt 159 out of the passageway and follows the belt around the drive capstan 183 and immediately thereafter the web is tripped from the belt and is passed around a porous air bearing 184, corresponding to the roller 158, to avoid scratching the web. From the bearing 184 the web is drawn into loop chamber 157 and then is taken up by a spool or reel in a cartridge immediately outside the loop chamber.

One surface of the belt 159 is disposed to contact the drive capstan and air pressure is used to clamp the belt 159 and web 155 together and in driving engagement with the drive capstan. The use of air to clamp the belt and web to the drive capstan 183 is successful in preventing slippage between the belt and web and is achieved by the use of a housing 186 containing a suitable chamber and positioned adjacent the drive capstan 183. The chamber opens toward the portion of the periphery of the capstan engaging the belt such that air under a positive pressure of about to pounds per square inch, pumped by a suitable pump 187 into the chamber, is directed against the web and belt forcing them against the drive capstan to afford good drive contact between the belt and web and between the capstan and the belt.

The several plates, blocks and the transport member forming the apparatus of the several embodiments are gas impermeable and preferably formed of steel. The web engaging surface of the plates, e.g., 86, 87, 88, and 89, forming the loop chambers are covered with a layer of velvet to protect the film.

When imaging successive frames on a film, where the frames have a millimeter format or larger, at a speed matching a useful and economical rate for a corpuscular beam the film must be moved rapidly. Greatest resolution is obtained when the beam impinges directly on the film. The film therefore must be passed into a highly evacuated area where such beams are operative. Also, complete exposure of a frame by focussing the beam on two axes is preferred and therefore the film should be substantially flat when exposed and the entire image formed with the film stationary. The above difiiculties can be overcome and optimum conditions afforded by placing the web on an endless movable transport which has a film supporting surface guided in a convex path through a circuitous high impedance passageway, which permits movement of the transport and web without interference or wrinkling, to an area of high vacuum and also in register with an aperture through which the beam is directed and focussed to impinge directly on the web. The Web, after reaching the area of high vacuum, may be lifted from the transport to be positioned in a planar position for treatment but is returned to the surface and conforms thereto for subsequent movement through an identical circuitous high impedance passageway out of the area of high vacuum. The film is then separated from the surface of the transport to be rewound, directed to a developer or otherwise used.

Having thus described the present invention it is to be understood that certain changes and modifications can be made without departing from the spirit or scope of the invention.

What is claimed is:

1. A method of imaging a film of at least 35 millimeter size comprising the steps of placing the film in contact with a movable flexible band for transporting the film progressively through a fixed defined circuitous passage of varying pressure and of dimensions only slightly greater than the cross-sectional dimensions of the film to a treatment area having a high vacuum atmosphere, successively positioning areas of the film in register with an aperture communicating directly with a treatment chamber under high vacuum and in which a corpuscular beam is generated and focussed through said aperture, impinging the beam on the successive areas of said film, transporting the film out of said treatment area through a fixed defined circuitous passage of varying pressure, and separating the film from the movable flexible band.

2. A method of imaging film of at least 35 millimeters comprising the steps of placing the film in contact with a movable endless band which follows a convex path through a circuitous passageway of varying pressure leading into a treating area under high vacuum, the dimensions of said passageway being only slightly greater than the cross-sectional dimensions of said film and said band, placing said film under tension to put it in intimate contact with said band, lifting the film from the band and upon advancing said film and said band positioning successive areas of the film in register with an aperture formed in a planar wall surface through which is directed a controlled corpuscular beam which impinges directly on the areas of said film to image the same, directing imaged areas of film back to said band, transporting the film out of said chamber through a circuitous passage of varying pressure, and separating the film from the band.

3. In apparatus for treating a surface of a web in the presence of a high vacuum as the web is moved progressively into and out of an at least partially evacuated atmosphere, the improvement comprising means defining an evacuatable treating chamber,

wall means including fixed concave and convex wall means defining an open arcuate passageway leading into and out of said chamber and a pair of at least partially evacuatable slotted openings located along and extending transversely of said passageway on each side of said chamber,

means for at least partially evacuating said treating chamber,

means for at least partially evacuating said slotted openings to afford differential pressures along said passageway on each side of said treating chamber to form a seal for said treating chamber,

movable transport means disposed within said passageway over said convex wall means and having a web supporting surface spaced from said concave wall means for carrying a said web into said chamber and out of said chamber, and

means for advancing said transport means through said passageway into and out of said chamber.

4. The combination of claim 3 wherein said passageway is arcuate in a lengthwise direction and straight in a transverse direction and the curvature in said lengthwise direction has a constant radius throughout the length of the passageway, and said passageway has a long narrow rectangular cross-section, with the greatest dimension in the transverse direction of said passageway.

5. The combination of claim 3 wherein said transport means is an endless band.

6. The combination of claim 3 wherein said transport means comprises a rigid circular band.

7. The combination of claim 3 wherein said passageway is formed at least in part by opposed spaced concentric concave and convex surfaces and said transport means is an endless band which is directed over said convex surface and said web-supporting surface or a said web thereon does not contact a guide throughout movement through said passageway.

8. The combination of claim 7 further comprising means defining a loop-forming chamber disposed adjacent each end of said passageway for drawing a said web toward and into contact with the Web supporting surface of said transport means when moving a said web through said apparatus.

9. The combination of claim 3 wherein said means for advancing said transport means comprises a drive capstan positioned adjacent one surface of said transport means and pressure-applying means to hold said transport means in driving engagement with said drive capstan.

10. The combination of claim 9 wherein said pressureapplying means comprises a housing disposed along the transport means on the side opposite said drive capstan and connected to a source of air pressure, said housing being formed with a chamber opening toward the portion of said drive capstan contacting said transport means to force said transport means against said drive capstan, and guide means for a said web directing said web into contact with said web supporting surface of said transport means and for directing said web from said surface after movement thereof with said transport means past said drive capstan.

11. In apparatus for treating a surface of a web in the presence of a high vacuum as the web is moved progressively into and out of an at least partially evacuated atmosphere, the improvement comprising means defining an evacuatable treating chamber, a circuitous open passageway leading into and out of said chamber, and a pair of at least partially evacuatable slotted openings located along and extending transversely of said passageway on each side of said chamber,

means for at least partially evacuating said treating chamber, means for at least partially evacuating said slotted openings to form a seal for said treating chamber,

transport means comprising a flexible band disposed within said passageway and having a web supporting surface, and

means for advancing said flexible band through said passageway into and out of said chamber.

12. In apparatus for treating a surface of a web in a high vacuum atmosphere, a web transport and vacuum chamber sealing structure permitting progressive movement of a web into and out of said high vacuum atmosphere comprising in combination evacuatable chamber means having an opening at one end,

block means positioned at said end of said chamber means, said block means having opposed spaced concave and convex surfaces with said concave surface communicating with said opening,

parallel wall members spaced apart an amount substantially greater than said surfaces and mating with said block means to define with said surfaces of said 10 block means an arcuate passageway leading toward and away from said opening,

means defining at least a pair of spaced partially evacuable transversely extending slotted openings in said concave surface disposed on each side of said opening and extending between said parallel walls, and defining grooves joining said slotted openings of a said pair on one side of said opening with similarly spaced slotted openings of said pair on the other side of said opening,

means for at least partially evacuating said chamber means, and for at least partially evacuating said joined ones of said slotted openings separately,

a band extending through said passageway over said convex surface and having a Web-supporting surface upon which to carry a Web in close proximity to said concave surface, and

means for advancing said band through said passageway.

13. The combination of claim 12 wherein said means for advancing said band comprises a drive capstan positioned adjacent one surface of said transport means and pressure-applying means to hold said band in driving engagement with said drive capstan.

14. The combination of claim 13 wherein said pressureapplying means comprises a housing disposed along the band on the side opposite said drive capstan and connected to a source of air pressure, said housing being formed with a chamber opening toward the portion of said drive capstan contacting said band to force said band against said drive capstan, and means guiding a said web onto the web supporting surface of said band for movement therewith through said passageway and be tween said housing and said drive capstan.

15. An apparatus for treating a surface of a web by directly impinging upon the surface of said web a controlled corpuscular beam, said apparatus comprising means defining a chamber having an opening at one end thereof, means within said chamber for generating and focussing a corpuscular beam at and through said opening, means for at least partially evacuating said chamber, a pair of spaced parallel plates, a first block disposed be tween and joining said pair of plates and said one end of said chamber, said first block being formed with an aperture aligned with the opening at the end of said chamber, said first block being further formed with a concave face communicating directly with said aperture and having arcuate surface portions which are of equal radius, concentric and disposed on said face on each side of said aperture, said arcuate surface portions being formed with slots extending transversely of said surface portions and between said plates, means for at least partially evacuating said slots, a second block having a convex semicylindrical surface, which second block is positioned between and joining said plates with said surface in closely spaced concentric relation with the arcuate surface portions of said face on said first block, roller means disposed on said second block, an endless band having a smooth web-supporting surface which has a width substantially equal to but not greater than the spacing between said plates, said band being disposed around said second block and supported at least partially on said roller means, means for advancing said band and a said web between said concave face and convex surface of said blocks and toward and away from said aperture in said first block to place one side of said web in regis-,

ter with said aperture soa said beam may impinge on said one side of said web, said means for advancing comprising a capstan, a pressure roller for pressing a web into engagement with said capstan, and a roller biased into engagement with said capstan and into engagement with said band such that rotation of said capstan advances said web and said band to pull said web and said band past said aperture, between said plates and over said convex surface.

1 l 1 2 16. An apparatus for imparting images, having a supporting surface which follows a convex path format of a size at least equal to that placed normally through said passageway which path is spaced from on 35 millimeter film, by means of a corpuscular beam said concave surface, onto a web comprising: guide means disposed adjacent said planar wall and evacuatable chamber means having an opening at one 5 spaced from said convex surface to define a path end, for a said web which lifts the web off the band and means for generating and controlling a corpuscular directs the same along a path parallel to said planar beam positioned in said chamber means and directwall and then back to the supporting surface of said ing said beam through said opening, band,

means joined to the end of said chamber means defin- 10 and means for placing a said web in contact with said ing opposed spaced concentric concave and convex supporting surface of said band and with said guide surfaces and transversely spaced parallel walls which means and for advancing a said web and band form a passageway leading across the end of said through said passageway.

chamber and defining a treatment area including a planar wall which is tangential to said concave sur- 5 References Cited face and joined thereto intermediate its ends through UNITED STATES PATENTS which is disposed an aperture communicating di- 1736 456 11/1929 Matthias 346110 rectly with the openlng 1n said chamber means, means defining transversely extending slots in said con- 34O9906 11/1968 Jones 346 11O cave surface adjacent the ends thereof, 20 means for at least partially evacuating said chamber JOSEPH HARTARY Pnmary Exammer means and said slots, US Cl an endless band extending through said passageway around said convex surface and having a web- 118-49 178 6-7 346 110 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,553, 7 9 Dated October 18 197].

Inventor(s) Derrick A. Jones It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 9, delete "aperature" and insert aperture Column 4, line 3, delete "prefereably" and insert preferably Column 1, line 20, delete "guade" and insert guide Column line, 26, delete "evecuated" and insert evacuated Column line 37, delete "therof" and insert thereof Column 4, line 60, delete "pressure" and insert vacuum treating Column 6, line 35, delete "serve" and insert serves Column 6, line 47, before "a" insert by Column 7, line 2 4, delete "emobdiment" and insert embodiment Column 7, line 35, delete "tripped" and insert stripped Signed and sealed this 21 st day of March 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTI'SGHALK Attesting Officer Commissioner of Patents can. nnlincn (Lem I a A l A n r n n e v k. 

